Photo of Japanese knotweed invading a site recorded during a walkover survey.

Japanese knotweed is a non-native invasive bamboo-like plant that is very strong and grows incredibly quickly. It can cause damage to drains, paths, walls and foundations. Many mortgage lenders will not agree to lend against a property that is located within 7m of the plant.

In the County Court case of Waistell v Network Rail (2017), Network Rail was ordered to pay compensation to two home owners whose properties backed on to Network Rail land which was rife with Japanese knotweed. This case potentially opens the way for claims against owners of land containing Japanese knotweed and to property professionals advising them. The AGS have published Loss Prevention Alert No 67 which reminds Members of the law relating to Japanese knotweed, describes the Waistell case and the reasoning behind the Court’s decision, and discusses the responsibility Members have relating to Japanese knotweed when advising their clients on the purchase of land or on construction activities. AGS Members should also be aware of other invasive species such as giant hogweed which land owners could have a responsibility to control.

The case is significant as it holds landowners to account and imposes a positive duty on them to ensure that any knotweed that is on their property is not preventing neighbouring landowners from being able to sell their property for market value.

Damages can be claimed for costs of removing the Japanese knotweed or an order requiring the defendant to remove it, costs of any remedial works to the claimant’s property and diminution in value of the property.

The full Loss Prevention Alert 67 – Japanese Knotweed – Professionals should know the law and their responsibilities can be downloaded here.

Further information on Japanese knotweed and related issues can be found on the following websites.
Environment Agency (www.environment-agency.gov.uk)
Scottish Environment Protection Agency (www.sepa.org.uk)
Royal Institution of Chartered Surveyors (www.rics.org/standards)
UK Government (www.gov.uk/guidance/prevent-japanese-knotweed-from-spreading)
The Invasive Non-Native Specialists Association (www.innsa.org)

This article was contributed by David Hutchinson, Honorary Member of the AGS and featured in the March/April 2018 issue of the AGS Magazine, which can be viewed here.